What channel are Email and SMS in GA4? Google's official .xlsx has the answer

Few operators can answer on the spot which GA4 (Google Analytics 4) channel a click from a newsletter, SMS, or web push notification ends up in. Guesses like "probably Referral or (other)" are common.

But the real answer is written into GA4's official "Default Channel Group" definition[1]. For every single visit, GA4 reads utm_source and utm_medium and auto-assigns it to one of the 23 channels[1] using a fixed rule set decided on Google's side. Operators cannot override it.

This article reads the official rules for Email, SMS, and Mobile Push — three channels where operators actively design their own UTMs. Pairing it with the sister utm_source pieces[2] gives a complete view of the Default Channel Group.

Key takeaways#

1. The correct Email channel value is utm_medium=email. utm_source can also trigger Email judgment, but utm_medium=email is the shortest cross-tool form
2. The correct SMS channel value is an exact match on utm_medium=sms. LINE and WhatsApp do not count as SMS — they fall into Referral
3. Mobile Push judgment uses 3 OR conditions. utm_medium ending in "push", containing mobile or notification, or utm_source=firebase — any one is enough

1. What is the Default Channel Group, and who decides it#

GA4's Default Channel Group auto-classifies every visit by checking utm_source × utm_medium against the official ruleset[1]. Operators cannot rename channels inside reports. Custom channel groups can be created separately, but the default-side rules are entirely fixed by Google[1].

Where the official judgment logic actually lives#

The judgment logic is split across 2 files:

• The channel definition itself: the Google Analytics Help page "[GA4] Default channel group" lists conditional expressions for all 23 channels[1]
• The Source Categories table: a 819-row .xlsx Google distributes[3], mapping each utm_source value to a category like SOCIAL, SEARCH, VIDEO, or SHOPPING

This article focuses on the former. The latter is unpacked in the sister TikTok / LinkedIn utm_source piece[2].

The full list of 23 channels GA4 officially defines#

The full list of 23 channels, in one image. Email, SMS, and Mobile Push are three of the channels where operators actively design UTMs themselves — and yet they are also the channels where misclassification happens most often.

Why operators can't touch the auto-classification#

Google fixes channel definitions so that GA4 reports remain comparable across sites[1]. If each operator could redefine "this is Email, this is Referral" arbitrarily, cross-industry benchmarking and reading GA4's own guides would break. Custom channel groups exist, but they live as "your own view" and cannot be mixed back into the default 23 channels by design.

2. The correct Email channel value — which UTMs land in Email#

What do you have to put on a newsletter URL to land in the GA4 Email channel? The official condition reads[1]:

Email: Source matches "email|e-mail|e_mail|e mail" OR Medium matches "email|e-mail|e\_mail|e mail"

It's an OR condition — either utm_source or utm_medium matching is enough. Four spellings are accepted (email / e-mail / e_mail / e mail), so hyphen, underscore, and space separators all pass.

The "I sent the newsletter but it isn't in Email" failure modes#

Three common failure modes:

• Setting utm_medium=newsletter: a literal translation of "newsletter" that isn't in the official 4 spellings. Lands in Paid Other or (other)
• Setting utm_medium=mail: missing the "e". mail alone doesn't match any of the 4 spellings and drops out of Email
• Setting utm_source=mailchimp only, with utm_medium empty: if the Source side doesn't contain the string "email", judgment fails. Forgetting utm_medium reliably sends it to Referral

When you want utm_source to carry the tool name (mailchimp, sendgrid, etc.), always pair it with utm_medium=email so the Medium-side condition triggers Email judgment.

Recommended format and a quick-reference table#

The recommended format for newsletter delivery:

utm_source=mailchimp     # tool name — your internal identifier
utm_medium=email         # shortest of the 4 official spellings
utm_campaign=2026-05-launch
utm_content=cta-button-top

How each utm_medium value gets classified, in one image:

3. The correct SMS channel value — do LINE and WhatsApp count as SMS#

The SMS channel condition is even simpler[1]:

SMS: Source is exactly "sms" OR Medium is exactly "sms"

Unlike Email, this is an exact match. Any spelling other than lowercase sms (including SMS in mixed case) drops out. GA4 stores values case-sensitively, so utm_source=SMS will not match[1].

Are LINE / WhatsApp counted as SMS? The official answer is "No"#

It's tempting to lump messaging channels together, but GA4's SMS rule only triggers on the literal string sms. Setting utm_source=line or utm_source=whatsapp does not trigger SMS judgment — instead it lands in Referral, Organic Social, or (other) depending on the Source Categories table[3].

The internal ask of "I want LINE Official Account traffic bucketed with SMS" cannot be satisfied through the default channel group. A practical workaround: build a custom channel group, or keep SMS as its own channel and separately tally utm_source=line inside Referral.

Recommended format and failure-pattern quick-reference#

The recommended format for SMS delivery and the value-by-value judgment table, in one image:

4. Quick-reference rules for Display, Mobile Push, Affiliates, and other major channels#

Beyond Email and SMS, the channels where operators most actively design UTMs are Display, Mobile Push, Affiliates, and Audio. The official conditions for each, in one image[1]:

Mobile Push in particular runs on 3 OR conditions. Any one of utm_medium=web-push, utm_medium=mobile-app, or utm_source=firebase is sufficient to land in Mobile Push[1]. URLs sent from a web push notification tool should always carry one of these on utm_medium.

A 3-step check for whether your channels are misclassified#

Once you know the official rules, here's how to verify how your own GA4 is actually classifying things:

1. Open GA4 "Acquisition" → "Traffic acquisition" and break down by "Default channel group"
2. Check whether the last 30 days show sessions in "Unassigned" or "(other)". If they do, UTMs that don't match the official conditions are mixed in
3. Decompose further with "Session source/medium" and read raw utm_source / utm_medium values to pinpoint which combinations are dropping out

If "Unassigned" or "(other)" exceeds 5%, suspect inconsistent UTM naming across the team running campaigns.

5. After GA4 classifies correctly, what you really want to see is revenue#

We've now decoded GA4's official Default Channel Group rules. But what operators ultimately want to know is "which channel is driving revenue". Of 1,000 sessions correctly classified as Email, how many converted and at what average order value — only then can you make a real investment call on email.

GA4 measures the traffic side (sessions by channel). The product I'm building, RevenueScope, is designed to go the other way — starting from revenue and resolving back to the channel, complementary to GA4. UTM values correctly classified in GA4 flow into RevenueScope at the session level, tied to RPS (Revenue Per Session) and AOV (Average Order Value), so you can see Email, SMS, and Mobile Push revenue contribution on one screen.

For self-managed ecommerce, "classify it correctly and stop there" isn't enough. Closing the loop between classification and revenue is what makes the operational decision possible.

Related articles in /news/en:

• What goes into utm_source for Meta Ads (pillar: utm_source side, official source categories)
• What goes into utm_medium for Meta Ads (same series: utm_medium side, official regex)
• What goes into utm_source for TikTok and LinkedIn Ads (same series: media-specific utm_source)
• Japanese version of this article

References#

1. Google Analytics Help « [GA4] Default channel group » May 2026
2. Google « GA4 Default Channel Group Source Categories (official distribution file · 819 entries) » Last checked May 2026